Side fire laser assembly

ABSTRACT

Embodiments include an apparatus including an optical fiber having a proximal end and a distal end. The distal end of the optical fiber has a surface configured to emit energy transverse to a longitudinal axis of the optical fiber. The apparatus also includes a tube including a channel, and the distal end of the optical fiber is disposed in the channel of the tube. The apparatus further includes an element disposed at a distal end of the tube such that a pocket is formed in the channel of the tube between the element and the distal end of the optical fiber.

This application is a Continuation Application of U.S. patentapplication Ser. No. 13/094,554, filed Apr. 26, 2011, currently pending,which is a non-provisional Patent Application of and claims the benefitof priority from U.S. Provisional Application No. 61/330,734, filed May3, 2010, all of which are herein incorporated by reference in theirentireties.

FIELD

Embodiments include medical devices and more particularly medicaldevices including a side fire laser assembly and related methods of use.

BACKGROUND

Side fire laser assemblies may be used for laser-based surgicalprocedures, for example, to deliver laser energy of a specificwavelength at a specific pulse rate to remove tissue throughvaporization. Such procedures may be performed in an aqueousenvironment, for example, under water.

FIGS. 1 and 2 show a conventional side fire laser assembly 100 includinga side fire optical fiber 130. An end 132 of the optical fiber 130 maybe polished at a specific angle such that energy is emitted to a side ofthe optical fiber, as opposed to the end. To permit the laser to emitenergy at the correct angle, an air interface is provided at thepolished end 132 of the optical fiber 130. As shown in FIG. 1, an airgap 160 is formed in the conventional laser assembly 100 when acapillary tube 150 is fused to the optical fiber 130 and an end 152 ofthe capillary tube 150 is heated until the end of the capillary tube 150collapses, thereby forming the air gap 160. As shown in FIG. 2, a metalcap 200 may be placed over the end 152 of the capillary tube 150. Duringa procedure, as noted below, up to 100 W (watts) of energy may passthrough the optical fiber 130 at pulse rates up to 50 Hz (Hertz). Thispulsed energy may create vapor bubbles upon exiting the optical fiber130. These vapor bubbles may collapse back violently onto the face ofthe optical fiber 130. The metal cap 200 helps to reinforce thecapillary tube 150 during energy delivery through the laser assembly100.

When using this conventional laser assembly 100, a portion of the laserenergy may leak from the distal end 132 of the optical fiber 130,thereby reducing the efficiency with which laser energy is delivered tothe treatment area in the patient and/or overheating the metal cap 200that is used to protect the optical fiber 130. For example, thisconventional laser assembly can operate at 100 W of average power. Thismeans that, for every second, 100 J (joules) of energy pass through theoptical fiber. The laser assembly can operate in a pulse mode with apulse rate of 50 Hz and a pulse duration of only 200 μs (microseconds).Each pulse therefore delivers 2 J (100 J/50 Hz) and 10,000 W of power (2J/200 μs=2 J/0.2×10⁻³ s=10×10³ W). The efficiency of energy transitionbetween the optical fiber and the outside media in the conventionallaser assembly may be 96-98%. This means that 2-4% of energy is lost bybeing converted to heat, creating about 200-400 W of heat for everypulse. Most of the loss by heat generation happens in a very smallvolume on the end of the capillary tube where the energy beam changesdirection and transits from glass into water. If the heat is notdissipated efficiently, the temperature in the end of the optical fibercan rise higher than the structure can handle.

Accordingly, cooling of the device may be needed to operate the laserassembly at a safe temperature. In some instances, the overheating thatcan occur from laser energy leakage can affect the mechanical and/oroptical properties of the end of the optical fiber, the capillary tube,and/or the metal cap. In other instances, the overheating that can occurfrom laser energy leakage can be sufficiently severe to damage the endof the optical fiber, the capillary tube, and/or the metal cap.

Besides high temperatures, intense vibrations may be generated duringeach laser pulse. These vibrations may cause glue that attaches themetal caps to the capillary tube to break away. As the glue dislodges,the capillary tube is allowed to vibrate more freely. The vibration ofthe capillary tube may be so intense that the glass of the capillarytube may begin to break or fracture.

Accordingly, a need exists for a laser assembly that can withstand hightemperatures and/or vibrations.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention.

SUMMARY

In accordance with an embodiment, an apparatus includes an optical fiberhaving a proximal end and a distal end. The distal end of the opticalfiber has a surface configured to emit energy transverse to alongitudinal axis of the optical fiber. The apparatus also includes atube including a channel, and the distal end of the optical fiber isdisposed in the channel of the tube. The apparatus further includes anelement disposed at a distal end of the tube such that a pocket isformed in the channel of the tube between the element and the distal endof the optical fiber.

In accordance with another embodiment, a method of forming an apparatusincludes disposing a distal end of an optical fiber within a channel ina tube. The optical fiber has a surface configured to emit energytransverse to a longitudinal axis of the optical fiber. The method alsoincludes forming a pocket in the channel of the tube between an elementand the distal end of the optical fiber by disposing the element at adistal end of the tube. A distal end of the element protrudes distallyfrom the distal end of the tube.

In accordance with a further embodiment, an apparatus includes anoptical fiber having a proximal end and a distal end. The distal end ofthe optical fiber has a surface configured to emit energy transverse toa longitudinal axis of the optical fiber. The apparatus also includes atube including a channel, and the distal end of the optical fiber isdisposed in the channel of the tube. The tube is disposed in a structureconfigured to maintain a compressive axial force on the tube.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out below.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of theinvention and together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a cross-sectional view of a distal end portion of aconventional laser assembly including a capillary tube and opticalfiber;

FIG. 2 is a cross-sectional view of the distal end portion of theconventional laser assembly of FIG. 1 with a metal cap disposed over thecapillary tube and optical fiber;

FIG. 3 is a schematic view of a laser assembly, according to anexemplary embodiment of the invention;

FIG. 4 is a cross-sectional view of a distal end portion of a laserassembly including a capillary tube and optical fiber, according to anexemplary embodiment of the invention;

FIG. 5 is a perspective view of the distal end portion of the laserassembly of FIG. 4 with a mandrel;

FIG. 6 is a perspective view of the distal end portion of the laserassembly of FIG. 4 with components for reducing vibration of the distalend portion; and

FIG. 7 is a perspective view of the distal end portion of the laserassembly of FIG. 4 with a cap.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to exemplary embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

The terms “proximal” and “distal” are used herein to refer to therelative positions of the components of an exemplary laser assembly 10.When used herein, “proximal” refers to a position relatively closer tothe exterior of the body or closer to the surgeon, or other user, usingthe laser assembly 10. In contrast, “distal” refers to a positionrelatively further away from the surgeon, or other user, using the laserassembly 10 or closer to the interior of the body.

The devices and methods described herein are generally related to theuse of side-firing optical fibers within the body of a patient. Forexample, the devices and methods may be suitable for use in treatingsymptoms related to an enlarged prostate gland, such as a conditionknown as Benign Prostatic Hyperplasia (BPH). BPH is a common conditionin which the prostate becomes enlarged with aging. Laser-based surgicalprocedures employing side-firing optical fibers and high-power lasersmay be used to remove obstructing prostate tissue, e.g., associated withBPH. In these procedures, a doctor may pass the optical fiber throughthe urethra using a cystoscope, a specialized endoscope with a smallcamera on the end, and then may deliver multiple pulses of laser energyto destroy some of the enlarged prostate tissue and to shrink the sizeof the prostate. The devices and methods described herein may be used totreat conditions of the body other than BPH.

FIG. 3 is a schematic drawing of a side fire laser assembly 10 accordingto an exemplary embodiment. The laser assembly 10 may include a distalend portion 12 and a proximal end portion 14. The laser assembly 10 mayalso include a laser source 20 and an optical fiber 30. The laser source20 may be located in the proximal end portion 14 of the laser assembly10, and the optical fiber 30 may extend between and into the proximaland distal end portions 12, 14 of the laser assembly 10. The laserassembly 10 may be used to transmit laser energy from the laser source20 to a target treatment area within a patient's body, e.g., near thedistal end portion 12 of the laser assembly 10.

The laser source 20 may include at least one laser that may be used togenerate laser energy for surgical procedures. The laser source 20 mayinclude at least one of, for example, a Ho:YAG laser, aneodymium-doped:YAG (Nd:YAG) laser, a semiconductor laser diode, or apotassium-titanyl phosphate crystal (KTP) laser. The laser source 20 mayinclude more than one laser, and more than one laser may be used duringa surgical procedure. The laser source 20 may also include a processorthat provides timing, wavelength, and/or power control of the laser(s).For example, the laser source 20 may include one or more mechanisms forlaser selection, filtering, temperature compensation, and/or Q-switchingoperations.

The optical fiber 30 may include a distal end 32 (FIGS. 4-7) and aproximal end 34. The proximal end 34 of the optical fiber 30 may becoupled to the laser source 20 in the proximal end portion 14 of thelaser assembly 10. For example, the proximal end 34 of the optical fiber30 may be coupled to the laser source 20 through an optical coupler 22in or near the proximal end portion 14 of the laser assembly 10. Theoptical coupler 22 may be, for example, an SMA (SubMiniature version A)connector. The proximal end 34 of the optical fiber 30 may be configuredto receive laser energy from the laser source 20 via the optical coupler22, and the optical fiber 30 may be configured to output the laserenergy through the distal end 32 of the optical fiber 30. The opticalfiber 30 may include, for example, a core, one or more cladding layersabout the core, a buffer layer about the cladding, a jacket, etc. Thecore may be made of a suitable material for the transmission of laserenergy from the laser source 20. The core may be multi-mode and may havea step or graded index profile. The cladding may be a single or a doublecladding that may be made of a hard polymer or silica. The buffer may bemade of a hard polymer such as Tefzel®, for example. When the opticalfiber 30 includes a jacket, the jacket may be made of Tefzel®, forexample, or other polymers. The optical fiber 30 may be made of asuitable biocompatible material and may be flexible, for example, totraverse tortuous anatomy in the body.

The laser assembly 10 may also include a suitable catheter or endoscope40 for inserting the distal end portion 12 of the laser assembly 10 intoa patient's body. The endoscope 40 may define one or more lumens. Insome embodiments, the endoscope 40 may include a single lumen that mayreceive various components such as the optical fiber 30. The endoscope40 may have a proximal end configured to receive the distal end 32 ofthe optical fiber 30 and a distal end configured to be inserted into apatient's body for positioning the distal end 32 of the optical fiber 30in an appropriate location for a laser-based surgical procedure. Forexample, to perform a surgical procedure near the prostate, theendoscope 40 may be used to place the distal end 32 of the optical fiber30 at or near the prostate gland. The endoscope 40 may be made of asuitable biocompatible material and may include an elongate portion thatmay be flexible to allow the elongate portion to be maneuvered withinthe body. The endoscope 40 may also be configured to receive variousother medical devices or tools through one or more lumens of theendoscope 40, such as, for example, irrigation and/or suction devices,forceps, drills, snares, needles, etc. In some embodiments, theendoscope 40 may include a fluid channel (not shown) coupled at aproximal end to a fluid source (not shown). The fluid channel may beused to irrigate an interior of the patient's body during a laser-basedsurgical procedure. In some embodiments, the endoscope 40 may include anoptical device (not shown), e.g., including an eyepiece coupled to aproximal end of the endoscope 40. The optical device may include anoptical fiber or other image transmission device, e.g., a wirelessdevice, that may be disposed in or on the endoscope 40, e.g., in a lumenor on a distal end of the endoscope 40, to transmit an image signal tothe surgeon. Such an embodiment allows a medical practitioner to viewthe interior of a patient's body through the eyepiece.

FIGS. 4-7 show a method of forming the distal end portion 12 of thelaser assembly 10, according to an exemplary embodiment. The distal endportion 12 of the laser assembly 10 may be formed using one or moresteps illustrated in FIGS. 4-7, to arrive at a final distal end portion12 shown in FIG. 7.

As shown in FIG. 4, the distal end 32 of the optical fiber 30 may forman angled portion 36 in the distal end portion 12 of the laser assembly10. The distal end portion 12 of the laser assembly 10 (including theangled portion 36) may be inserted into the patient's body to providelaser treatment. An optical beam (e.g., laser beam including laserenergy) may be transmitted from the laser source 20, through the opticalfiber 30 from its proximal end 34 to its distal end 32, and then throughthe angled portion 36 at the distal end 32 of the optical fiber 30. Theangled portion 36 may be cleaved and/or polished to an appropriate angleconfigured to redirect laser energy in a lateral direction forside-firing transmission of laser energy to the area of treatment in thepatient's body. Thus, the distal end 32 of the optical fiber 30 mayinclude one or more members, elements, or components that mayindividually or collectively operate to transmit laser energy in alateral direction offset from a longitudinal axis or centerline of thedistal end 32 of the optical fiber 30.

The distal end 32 of the optical fiber 30 may be disposed within achannel 56 in a capillary tube 50 in the distal end portion 12 of thelaser assembly 10. The capillary tube 50 may include a distal end 52 anda proximal end 54, and the channel 56 may extend longitudinally betweenthe distal and proximal ends 52, 54. The capillary tube 50 may be madeof, for example, at least one of silica, sapphire, glass, and/or otherlike materials. An outer surface of the distal end 32 of the opticalfiber 30 may be fused or attached to an inner surface of the capillarytube 50. The proximal end 54 of the capillary tube 50 may be formed atan angle to have a frustoconical shape, as shown in FIGS. 4 and 5, orflat. The distal end 52 of the capillary tube 50 may also be formed atan angle to have a frustoconical shape or flat, as shown in FIGS. 4 and5.

The optical fiber 30 may be disposed through a proximal part of thechannel 56 in the capillary tube 50. For example, the distal end 32 ofthe optical fiber 30 may be inserted into the proximal end 54 of thecapillary tube 50 such that the channel 56 remains at least partiallyempty and the capillary tube 50 is open-ended at its distal end 52, asshown in FIG. 4. As shown, the distal end 52 of the capillary tube 50 isdistal to the angled portion 36 of the optical fiber 30. Since thechannel 56 is at least partially empty, a gap 60 is formed in thechannel 56 at a location that is distal from the distal end 32 of theoptical fiber 30. Also, the distal end 52 of the capillary tube 50 maybe kept flat, i.e., not rounded, and unmelted, as shown in FIG. 4.

As shown in FIG. 5, a mandrel 70 or other like-shaped cylinder or rodmay be inserted into the open end of the channel 56 in the capillarytube 50 in the distal end portion 12 of the laser assembly 10. Themandrel 70 may include a distal end 72 and a proximal end 74. An outersurface of the proximal end 74 of the mandrel 70 may be attached, suchas with an adhesive or glue, to an inner surface of the capillary tube50. At least a portion of the mandrel 70 and/or a coating on the mandrel70 may include a material that aids in the absorption or conduction ofenergy or heat away from the interior of the capillary tube 50. Themandrel 70 may dissipate the energy or heat. For example, at least aportion of the mandrel 70 and/or a coating on the mandrel 70 may be madeof, for example, a metal, metal alloy, and/or other thermally conductivematerial. Some nonlimiting examples include silver, copper, nickel,aluminum, stainless steel, titanium, tungsten (which has a highermelting point temperature), beryllium copper, etc.

The mandrel 70 may be disposed in a distal part of the channel 56 in thecapillary tube 50. Furthermore, the proximal end 74 of the mandrel 70may be inserted through the distal end 52 of the capillary tube 50 suchthat the channel 56 in the capillary tube 50 is at least partially emptybetween the proximal end 74 of the mandrel 70 and the distal end 32 ofthe optical fiber 30, as shown in FIG. 5. Thus, an air pocket 62 may beformed between the proximal end 74 of the mandrel 70 and the distal end32 of the optical fiber 30. The mandrel 70 and the optical fiber 30 actas seals at the respective ends of the channel 56 of the capillary tube50 to form the air pocket 62. Accordingly, it is not necessary to meltthe distal end 52 of the capillary tube 50 to form the air pocket 62.The mandrel 70 extends past and protrudes from the distal end 52 of thecapillary tube 50 so that the distal end 72 of the mandrel 70 is distalto the distal end 52.

The mandrel 70 may conduct heat produced through the energy transitionfrom the optical fiber 30 to the surrounding water environment, asdescribed above, more efficiently. As a result, the temperature of thedistal end portion 12 of the laser assembly 10 may be prevented fromincreasing too high, and the mandrel 70 acts as a heat sink. Forexample, heat may be conducted from the distal end 32 of the opticalfiber 30, through the air pocket 62, through the mandrel 70, and then tothe water environment surrounding the distal end portion 12 of the laserassembly 10. Thus, heat may be conducted out of the channel 56 of thecapillary tube 50, and the temperature increase in the capillary tube 50may be reduced (as compared to conventional devices), substantiallyinhibited, and/or prevented, which prevents overheating of the capillarytube 50 and/or the optical fiber 30.

As a result, providing the mandrel 70 in the distal end portion 12 ofthe laser assembly 10 allows, for example, an open-ended capillary tube50 that is not melted at its tip, transfer of heat from inside thecapillary tube 50 to the cooler water environment surrounding the distalend portion 12 of the laser assembly 10 through the thermally conductivemandrel 70, and/or absorption of a majority of stray laser energy thatmay escape through the distal end 32 of the optical fiber 30.

As shown in FIG. 6, a first component 80 may be disposed around themandrel 70 and against the distal end 52 of the capillary tube 50 in thedistal end portion 12 of the laser assembly 10. Alternatively, the firstcomponent 80 may be disposed against the distal end 72 of the mandrel70, around the distal end 52 of the capillary tube 50, or in otherpositions that allow the first component 80 to exert a force against thecapillary tube 50 in the proximal direction. As a result, the firstcomponent 80 may assist in providing a compressive load on the capillarytube 50 along its longitudinal axis.

A second component 82 may be disposed against the proximal end 54 of thecapillary tube 50 and around the optical fiber 30 in the distal endportion 12 of the laser assembly 10. Alternatively, the second component82 may be disposed around the proximal end 54 of the capillary tube 50,or in other positions that allow the second component 82 to exert aforce against the capillary tube 50 in the distal direction. As aresult, the second component 82 may also assist in providing acompressive load on the capillary tube 50 along its longitudinal axis.

The first and second components 80, 82 may be made of, for example, athermally conductive material, such as metal or metal alloy, and/orother like materials as described above. As a result, the first andsecond components 80, 82 may transfer heat from the capillary tube 50 tothe cooler water environment surrounding the distal end portion 12 ofthe laser assembly 10. Also, the first and second components 80, 82 maysandwich the capillary tube 50, and a compressive axial load may beapplied to the capillary tube 50 via the first and second components 80,82. The compressive axial load may be applied to the capillary tube 50by forcing together the first and second components 80, 82, for example,using a tool or a machine (e.g., to apply a predetermined load), or byhand as known in the art. It is to be understood that other suitablestructures known in the art that are capable of applying or transmittinga compressive axial load on the capillary tube 50 may be used.

A gasket 84 may be disposed between the first component 80 and thedistal end 52 of the capillary tube 50, and around the mandrel 70.Alternatively, an additional gasket (not shown) may be disposed betweenthe second component 82 and the proximal end 54 of the capillary tube50. The gasket 84 may be made, for example, of rubber and/or othercompressible materials, and/or other materials that allow the gasket 84to act to relieve strain on the capillary tube 50, e.g., when highpressure forces from vibrations act on the capillary tube 50. Thegasket(s) 84 may include a hole through which the mandrel 70, as shownin FIGS. 6 and 7, or the optical fiber 30 may be inserted.

The first component 80 may include a channel that receives the mandrel70, as shown in FIGS. 6 and 7. For example, the first component 80 maybe cylindrical. The first component 80 may have a varying cross-section.For example, the outer surface of the first component 80 may have astepped configuration as shown in FIGS. 6 and 7, which includes twosections with outer surfaces having different diameters, or may betapered. Alternatively, the first component 80 may have a constantcross-section, as shown in connection with the second component 82 inFIGS. 6 and 7. The channel or proximal end of the first component 80 maybe connected to the mandrel 70, the gasket 84, and/or the capillary tube50 (e.g., the distal end 52, if no gasket 84 is provided) using, forexample, an adhesive or glue, by friction fit, etc.

As shown in FIGS. 6 and 7, the first component 80 and the gasket 84 maybe inserted over the mandrel 70 so that the distal end 72 of the mandrel70 extends past and protrudes from a distal end of the first component80, and so that the distal end 72 of the mandrel 70 is distal to thedistal end of the first component 80. Alternatively, the first component80 and/or the gasket 84 may not include a channel or hole, and themandrel 70 may abut the first component 80 (or the gasket 84) such thatthe distal end 72 of the mandrel 70 is proximal to the first component80 (or the gasket 84). As another alternative, the first component 80may include a channel that extends only partially through the firstcomponent 80, and the mandrel 70 may be inserted into the channel sothat the distal end 72 of the mandrel 70 is disposed inside the firstcomponent 80 between the distal and proximal ends of the first component80.

The second component 82 may include a channel that receives the opticalfiber 30, as shown in FIGS. 6 and 7. For example, the second component82 may be cylindrical. The second component 82 may be of constantcross-section, as shown in FIGS. 6 and 7, or of varying cross-section,as described above in connection with the first component 80. Thechannel or the distal end of the second component 82 may be connected tothe optical fiber 30, a gasket (if provided), and/or the capillary tube50 (e.g., the proximal end 54) using, for example, an adhesive or glue,by friction fit, etc.

As noted above, the distal end 52 and/or proximal end 54 of thecapillary tube 50 may be formed at an angle (e.g., having afrustoconical shape) or flat. Accordingly, the gasket(s) 84 andrespective ends of the first and second components 80, 82 may also beformed at an angle (e.g., having a surface configured to correspondinglyreceive the frustoconical shape of the ends 52, 54 of the capillary tube50) or flat, as shown in FIGS. 6 and 7.

As shown in FIG. 7, after applying the compressive axial load using thefirst and second components 80, 82, a supportive cap 90 or overtube maybe inserted over and attached to the first and second components 80, 82,the respective gasket(s) 84, and/or the capillary tube 50 in the distalend portion 12 of the laser assembly 10. Thus, the cap 90 may serve as adistal casing for and/or may enclose the first component 80, the secondcomponent 82, the respective gasket(s) 84, and/or the capillary tube 50.The cap 90 may include a hypotube or other structure sized appropriatelyto receive and hold the different components together. The cap 90 mayconnect to the first and second components 80, 82, the respectivegasket(s) 84, and/or the capillary tube 50 using, for example, anadhesive or glue, by friction fit, etc. The cap 90 may also include awindow 92, for example, laser cut in the cap 90, for the energy deliveryfrom the angled portion 36 of the optical fiber 30 through the cap 90.The cap 90 may be made, for example, of a biocompatible and thermallyconductive material, such as metal or metal alloy, and/or other likematerials as described above. The cap 90 may have a length extendingfrom a proximal end of the second component 82 to a distal end of thefirst component 80, as shown in FIG. 7. Alternatively, the cap 90 mayextend distally from the proximal end of the second component 82 to abutthe step midway between the proximal and distal ends of the firstcomponent 80.

The cap 90 may assist in holding the capillary tube 50 sandwichedbetween the first and second components 80, 82 and may assist inmaintaining the compressive axial load on the capillary tube 50 appliedby the first and second components 80, 82. The compressive axial loadmay reduce the amount of vibrations in the distal end portion 12 of thelaser assembly 10. As noted above, each laser pulse from the lasersource 20 is capable of generating very intense vibrations, and thevibrations on the capillary tube 50 may cause the capillary tube 50 tobreak or fracture. Since the compressive axial load applied by the firstand second components 80, 82 may reduce these vibrations, providing thefirst and second components 80, 82 may prevent breakage or fracture ofthe capillary tube 50.

As described above, the distal end portion 12 of the laser assembly 10may be formed using one or more steps illustrated in FIGS. 4-7. Forexample, in some embodiments, the distal end portion 12 of the laserassembly 10 may be formed using the steps shown in FIGS. 4 and 5 withrespect to inserting the mandrel 70 into the capillary tube 50 withoutapplying a compressive axial force as shown in FIGS. 6 and 7. In otherembodiments, the distal end portion 12 of the laser assembly 10 may beformed using the steps shown in FIGS. 6 and 7 with respect to applying acompressive axial force without inserting the mandrel 70 into thecapillary tube 50.

Any aspect set forth in any embodiment may be used with any otherembodiment set forth herein. Every device and apparatus set forth hereinmay be used in any suitable medical procedure, may be advanced throughany suitable body lumen and body cavity, and may be used for treatmentof any suitable body portion. For example, the apparatuses and methodsdescribed herein may be used in any natural body lumen or tract,including those accessed orally, vaginally, or rectally.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the disclosed systems andprocesses without departing from the scope of the invention. Otherembodiments of the invention will be apparent to those skilled in theart from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only. The following disclosureidentifies some other exemplary embodiments.

In some embodiments, an apparatus may include an optical fiber having aproximal end and a distal end. The distal end of the optical fiber mayhave a surface configured to emit energy transverse to a longitudinalaxis of the optical fiber. The apparatus may also include a tubeincluding a channel, and the distal end of the optical fiber may bedisposed in the channel of the tube. The apparatus may further includean element disposed at a distal end of the tube such that a pocket isformed in the channel of the tube between the element and the distal endof the optical fiber.

In some embodiments, the element may form a seal on the distal end ofthe tube.

In some embodiments, a proximal end of the element may be disposedwithin a distal end of the tube.

In some embodiments, the element may include or be coated with amaterial configured to transfer heat from inside the tube to outside thetube.

In some embodiments, the element may include or be coated with amaterial configured to conduct energy transmitted through the distal endof the optical fiber.

In some embodiments, the element may be a metal rod.

In some embodiments, the pocket may be an air pocket.

In some embodiments, the distal end of the tube may be cylindrical andopen-ended.

In some embodiments, the apparatus may further include a laser source.The proximal end of the optical fiber may be configured to be coupled tothe laser source, and the apparatus may be a laser assembly.

In some embodiments, the tube may be compressed under a compressiveaxial force.

In some embodiments, the apparatus may further include a first componentdisposed at a distal end of the tube and a second component disposed ata proximal end of the tube. The first and second components may beconfigured to apply the compressive axial force on the tube.

In some embodiments, the apparatus may further include a cap configuredto attach the first and second components to the tube.

In some embodiments, the apparatus may further include at least onegasket disposed between the tube and at least one of the first andsecond components.

In some embodiments, a method of forming an apparatus may includedisposing a distal end of an optical fiber within a channel in a tube.The optical fiber may have a surface configured to emit energytransverse to a longitudinal axis of the optical fiber. The method mayalso include forming a pocket in the channel of the tube between anelement and the distal end of the optical fiber by disposing the elementat a distal end of the tube. A distal end of the element may protrudedistally from the distal end of the tube.

In some embodiments, the method may further include forming a sealbetween the element and the distal end of the tube, and the seal mayprevent fluid from entering the channel in the tube.

In some embodiments, the method may further include applying acompressive axial force on the tube and inserting the compressed tubeinto a tubular structure to maintain the compressive axial force on thetube.

In some embodiments, applying the compressive axial force on the tubemay include disposing a first component near the distal end of the tubeand disposing a second component near a proximal end of the tube. Thecompressive axial force may be applied to the tube using the first andsecond components.

In some embodiments, an apparatus may include an optical fiber having aproximal end and a distal end. The distal end of the optical fiber mayhave a surface configured to emit energy transverse to a longitudinalaxis of the optical fiber. The apparatus may also include a tubeincluding a channel. The distal end of the optical fiber may be disposedin the channel of the tube, and the tube may be disposed in a structureconfigured to maintain a compressive axial force on the tube.

In some embodiments, the structure configured to maintain thecompressive axial force on the tube may include a first componentdisposed at a distal end of the tube and a second component disposed ata proximal end of the tube. The first and second components may beconfigured to apply the compressive axial force on the tube.

In some embodiments, the structure configured to maintain thecompressive axial force on the tube may further include a cap configuredto attach the first and second components to the tube.

What is claimed is:
 1. An apparatus comprising: an optical fiber havinga proximal end and a distal end, the distal end of the optical fiberhaving a surface configured to emit energy at an off-axis angle relativeto a longitudinal axis of the optical fiber; a tube including a channel,the distal end of the optical fiber being disposed in the channel of thetube, wherein the tube is maintained under a compressive axial forceduring use; and an element disposed at a distal end of the tube andconfigured to form a pocket in the channel of the tube between theelement and the distal end of the optical fiber.
 2. The apparatus ofclaim 1, wherein the element includes a material configured to transferheat from inside the tube to outside the tube.
 3. The apparatus of claim1, wherein the element is a metal rod.
 4. The apparatus of claim 1,wherein the pocket is an air pocket.
 5. The apparatus of claim 1,wherein the distal end of the tube is cylindrical and open-ended.
 6. Theapparatus of claim 1, wherein a distal end of the element extendsdistally of a distal end of the tube.
 7. The apparatus of claim 1,wherein a proximal end of the tube comprises a frustoconical shape. 8.The apparatus of claim 1, wherein an outer surface of the element iscoupled to an inner surface of the tube via at least one of glue oradhesive.
 9. The apparatus of claim 1, further including: a lasersource, the proximal end of the optical fiber being configured to becoupled to the laser source, and the apparatus being a laser assembly.10. An apparatus comprising: a tube having a first end, a second end,and a channel extending between the first and second ends, wherein thetube is compressed under a compressive axial force during use; anoptical fiber having a proximal end and a distal end, the distal end ofthe optical fiber having a surface configured to emit energy at anoff-axis angle relative to a longitudinal axis of the optical fiber, theoptical fiber being located within the first end of the channel; and anelement being located within the second end of the channel.
 11. Theapparatus of claim 10, wherein a distal end of the element extendsdistally of a distal end of the tube.
 12. The apparatus of claim 10,wherein the element is coated with a material configured to transferheat from inside the tube to outside the tube.
 13. The apparatus ofclaim 10, further comprising: a first component positioned proximate thesecond end of the tube and a second component positioned proximate thefirst end of the tube, wherein each of the first and second componentsare configured to facilitate application of the compressive axial forceon the tube.
 14. The apparatus of claim 13, further comprising: at leastone compressible gasket positioned between the first component and thesecond end of the tube, or between the second component and the firstend of the tube.
 15. The apparatus of claim 10, further comprising: anovertube enclosing the first and second components and the tube.
 16. Theapparatus of claim 15, wherein the overtube comprises a hypotube. 17.The apparatus of claim 15, wherein the overtube includes a windowextending through a side wall of the overtube and configured to passenergy emitted by the optical fiber therethrough.
 18. An apparatuscomprising: a tube having a first end, a second end, and a channelextending between the first and second ends, wherein the tube is securedwith a compressive axial preload; an optical fiber having a proximal endand a distal end, the distal end of the optical fiber having a surfaceconfigured to emit energy at an off-axis angle relative to alongitudinal axis of the optical fiber, the optical fiber being locatedwithin the first end of the channel; an element being located within thesecond end of the channel; and an overtube enclosing the tube andconfigured to maintain the compressive axial preload on the tube. 19.The apparatus of claim 18, wherein the element is a metal rod.
 20. Theapparatus of claim 18, wherein the element is coated with a materialconfigured to conduct energy transmitted through the distal end of theoptical fiber.